Molten metal refining apparatus



July 26, 1966 D. c. STAFFORD MOLTEN METAL REFINING APPARATUS 4 Sheets-Sheet 1 Filed June 28, 1963 y 1966 D. c. STAFFORD 3,262,690

MOLTEN METAL REFINING APPARATUS VEN TOR.

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July 26, 1966 D. c. STAFFORD 3,262,690

MOLTEN METAL REFINING APPARATUS Filed June 28, 1963 4 Sheets-Sheet 4 United States Patent 3,262,690 MOLTEN METAL REFINING APPARATUS Donald C. Stafford, Homewood, Ill., assignor to Chicago Bridge & Iron Company, Oak Brook, 111., a corporation of Illinois Filed June 28, 1963, Ser. No. 291,568 17 Claims. (Cl. 266-35) The present invention relates generally to molten metal refining apparatus and to metallurgical vessels and more particularly to apparatus, of the type known in the steel industry as a basic oxygen converter, and which includes a rotatable vessel having a shell directly connected to the end pins about the axis of which the vessel is rotated.

Molten metal refining apparatus, of the type to which the present invention relates generally, typically comprises a refractory lined vessel for holding molten metal, with the vessel having a top opening for receiving an oxygen lance which is introduced into the interior of the vessel for refining the molten metal by oxidizing out impurities. The refining operation is exothermic and tremendous quantities of heat are generated. -At the conclusion of the refining operation the vessel is rotated about a horizontal axis and the.molten ingredients are poured out.

Rotatable mounting means for the vessel described above generally includes a pair of pins each extending from an opposite side of the vessel, in a horizontal direction along the axis of rotation, with each of the pins rotatably mounted on a respective stationary pedestal. Because of the tremendous amount of heat generated in the vessel druing the refining operation, attachment of the pins to-the shell of the vessel has raised a number of problems. 7

For example, in one conventional arrangement, the axially inner end of a pin is attached to a box-like structure having innermost edges defining an opening at the inn-erend of the box; and the box is welded at its innermost edges to the outer surface of the shell of the vessel. A drawback of this type of arrangement is that the boxlike structure welded to the vessel shell is at a different temperature than the vessel shell during the refining operation and restricts outward thermal expansion of the shell. This causes periodic build-ups and relaxations of stresses in the shell in accordance with periodic heat-ups and cool-downs of the shell during the refining operation. As a result, a crack eventually develops in the shell of the vessel.

Another coventional arrangement is to attach the inner end of each pin to a hollow annular ring located around the vessel and spaced radially therefrom. This, however, requires a complicated mounting arrangement for connecting the annular ring to the shell so as to accommodate radial and vertical expansion on the part of the vessel during a refining operation. Without this complicated mounting arrangement the vessel will undergo a vertical drop when it is rotated to an inverted position for pouring; and such a drop can damage the apparatus, especially if such a drop occurs repeatedly.

The present invention eliminates the above-described drawbacks and also provides an extremely simple, economical arrangement for connecting the end pins to the vessel. In a vessel constructed in accordance with the present invention, the pins are directly connected to the shell of the vessel and the shell of the vessel is selfsupporting.

More specifically, the vessel includes a crucible portion having a shell defined by a surface disposed around a crucible axis extending transversely to the axis of the pins, with the surface having a pair of cut-outs each on an opposite side of the shell axis and each disposed about or encircling the axis of the pins. The crucible shell surfaceis preferably symmetrical about the crucible shell axis. The axially inner portion of each pin is connected to a respective opposite side of the crucible portion by connecting means including a shell defined by a surface disposed around or encircling the pin axis and which may be a surface of revolution having the axis of its respective pin as a linear directrix and having a generatrix whose radial spacing from the pin axis decreases in an outward direction relative to the pin.

The crucible portion shell terminates, in an outward I direction along the axis of the pins, and on each side of the crucible axis, at a side peripheral edge defined by a respective one of the aforementioned cut-outs on the shell surface. The shell of each connecting means terminates, in an inward direction along the axis of the pins, at an inner peripheral edge having the same dimensions as an adjacent side peripheral edge of the crucible shell. The inner peripheral edge of a connecting means shell is in abutting relation with the adjacent side peripheral edge of the crucible shell around the entirety of each peripheral edge. As a result, the shell of each connecting means constitutes a smooth uninterrupted continuation of a shell of the crucible portion.

During the refining operation, molten slag is blown out of the interior of the vessel, and much of it lands on the outer surface of the vessel. A smooth continuous shell, without obstructions or projections extending therefrom, is advantageous in that it prevents accumulations of slag along the outer surface of the shell, as would otherwise occur if the shell were not constructed in the smooth continuous manner described above.

The innermost end or" each pin is located within the shell of the connecting means. The outermost end of the shell is rotatably mounted on stationary pedestals in a conventional manner.

Because the connecting means shell is attached to the crucible portion shell in the end or edge-abutting relation, there is no danger of the vessel shell cracking because of periodic build-ups and relaxations of stresses, as would be the case if the connecting means shell were merely welded to the outer surface of the crucible portion shell.

Because constructing a vessel and apparatus in accordance with the present invention eliminates the need for an annular mounting ring, the entire outer surface of the vessel is subject to inspection and observation, and hot spots occurring on portions of the shell, which otherwise would be hidden in an arrangement utilizing an annular ring, are readily observable and can be corrected before undue damage results from the hot spots.

Other features and advantages are inherent in the construction claimed and disclosed or will become apparent to those skilled in the art from the following detailed description in conjunction with the accompanying diagrammatic drawings wherein:

FIGURE 1 is a vertical elevational View, partially cut away, and illustrating one embodiment of molten metal refining apparatus constructed in accordance with the present invention;

FIGURE 2 is an elevational view, partially cut away, illustrating another embodiment of apparatus constructed in accordance with the present invention;

FIGURE 3 is an enlarged plan view of a metallurgical vessel and apparatus constructed in accordance with the present invention;

FIGURE 4 is a vertical sectional view of the apparatus illustrated in FIGURE 3;

FIGURE 5 is a sectional view taken along line 55 in FIGURE 4;

FIGURE 6 is a vertical sectional view of another embodiment of metallurgical apparatus;

FIGURE 7 is a sectional view taken along line 77 in FIGURE 6;

FIGURE 8 is an enlarged fragmentary sectional View illustrating the edge-abutting relation of the crucible shell and connecting means shell;

FIGURE 9 is a vertical sectional view of a further embodiment of apparatus in accordance with the present invention;

FIGURE 10 is a side elevational view of still another embodiment of apparatus; and

FIGURE 11 is a plan view of the apparatus of FIG- UR'E 10.

Referring initially to FIGURE 1 there is illustrated molten metal refining apparatus, indicated generally at 10, constructed in accordance with the present invention and comprising a vessel 11 from opposite ends of which extend mounting pins 12 each rotatably mounted on a pedestal 13 supported by a floor beam 14 resting atop columns 15. One of the end pins 13 is drivingly connected to motive means (not shown). Extending upwardly from floor beam 14 is an upright 16 to which is connected means 17 slidably reciprocally mounting an angularly extending oxygen lance 18 movable into and out of the opening 20 of vessel 11 to perform the refining operation. Also mounted atop floor beam 14 is a hood 21 for carrying away gases, smoke and fumes generated during the refining operation and billowing forth out of the opening 20 in vessel 11.

Referring now to FIGURE 2, in the embodiment of molten metal refining apparatus illustrated therein, an oxygen lance 28 extends vertically through the opening 20 in the vessel 11. The upper end of lance 28 is connected to the lower end of a cable 27 having an upper end trained around a reel 26 mounted on a bracket 25 connected to overhead structure 24. Reel 26 is operated to move lance 28 in and out of vessel 11 at the beginning and end respectively of the refining operation.

Referring now to FIGURE 3, 4 and 5, the vessel 11 comprises a crucible portion shell defined by a surface constituting a first surface of revolution 47 having a linear directrix or crucible shell axis (dash-dot line 41) extending transversely to the axis (dash-dot line 42) of pins 12, and by a pair of planes (dash-dot lines 43) each extending transversely to the axis 42 of pins 12 and each intersecting surface of revolution 47 on an opposite side of the directrix 41 to form cut-outs 70 on the surface.

Fixedly connecting the axially inner portion 62 of a respective end pin 12 at a respective opposite side of crucible portion shell 40, is connecting means 22 having a shell 44 defined by a second surface of revolution 48 having the axis 42 of the pins as a linear directrix and having a generatn'x whose radial distance from pin axis 42 decreases in an outward direction along pin 12.

Crucible shell 40 terminates, in an outward direction along pin axis 42, and on each side of crucible directrix 41, at a side peripheral edge 45 defining cut-out 70 and lying in a respective one of said planes 43 intersecting the first surface of revolution. The shell 44 of each connecting means 22 terminates, in an inward direction along pin axis 42, at an inner peripheral edge 46 lying in the same plane 43 as that in which an adjacent side peripheral edge 45 of crucible shell 40 lies. The inner peripheral edge 46 of each connecting means shell 44 has the same dimensions as and is in abutting relation with the adjacent side peripheral edge 45 of crucible shell 40 around the entirety of each peripheral edge. The edges 45, 46 are welded in the abutting relation illustrated in FIG- URES 3, 4 and-8. As a result, connecting means shell 44 constitutes a smooth uninterrupted continuation of crucible portion shell 40; and the shell of the entire vessel 11 has no projections or obstructions for facilitating the undesirable accumulation of slag blown out from the interior of vessel 11 through opening 20 during the refining operation. Slag falling on shells 40, 44 will drop olf the shells.

Connecting means 22 includes a terminal portion 50 constituting a hub for a respective end pin 12. More specifically, referring to FIGURES 4 and 5, terminal portion 50 includes an outer surface or shell portion 64 constituting a continuation of connecting means shell 44, an inner end plate 51, and an outer end plate 53 which, in the illustrated embodiment, lies in a plane parallel to plane 43 and is located outwardly thereof along pin axis 42. Located between inner end plate 51 and outer end plate 53 is a tubular portion 55 which receives the axially inner end portion 62 of end pin 12 which is welded to hub 50, as at 58.

Extending between cylindrical portion 55 and outer shell portion 64 are brace members 56; and located in outer shell portion 64 are vent openings 57 for permitting circulation of air around tubular portion 55 containing end pin inner portion 62.

As illustrated in the drawings, connecting means 22 has the shape of the frustum of a cone, this being a preferred form for the connecting means because it is relatively simple to fabricate compared to a spherical or elliptical portion. However, it should be noted that, in its broadest sense, the invention is not limited to connecting means having a form of the frustum of a cone. So long as the connecting means includes a shell having the form de scribed in previous para-graphs and connected to the crucible portion in the relationship previously described, it comes within the scope of the present invention.

The interior of vessel 11 is lined with refractory material 60; and around the upper opening 20 of vessel 11 in an annular plate 61.

Referring now to FIGURES 6 and 7 there is illustrated another embodiment of a vessel 111 from opposite ends of which extend end pins 112 each rotatably mounted on a respective pedestal 113. At least one end pin 112 is drivingly connected, by conventional means not shown, to motive means (not shown).

Vessel 111 comprises a bottle-shaped crucible portion constituting a shell defined by a first surface of revolution 149 having a linear directrix 141 extending transversely to the axis 142 of pins 112 and by a pair of planes 143 each extend-ing transversely to pin axis 142 and each intersecting the surface of revolution .of crucible shell 140 a on an opposite side of directric 141.

Fixedly connecting the axially inner portion 162 of pin 112 to crucible portion shell 140 is connecting means 122 having a shell 144 defined by a surface of revolution 148 having pin axis 142 as a linear directrix and having a generatrix Whose radial spacing fro-m the pin axis decreases in an outward direction relative to pin 112. Crucible portion shell 140 terminates, in an outward direction along the axis of pins 142, and on each side of the crucible directrix 141, at a side peripheral edge 145 lying in a respective one of the planes 143 intersecting first surface of revolution 149. The shell 144 of each connecting means 122 terminates in an inward direction along axis 142 at an inner peripheral edge 146 lying in the same plane as that in which an adjacent peripheral edge 145 of crucible shell 140 lies. Connecting means inner peripheral edge 146 is in abutting relation with the adjacent side peripheral edge 145 of crucible shell 140 around the entirety of each peripheral edge.

Describing connecting means 122 now in greater detail, there is included, in addition to shell 144, an inner plate 151 constituting -a retaining wall for the refractory lining 160 on the interior of the vessel 111. Plate 151 is connected to a tubular portion 155 extending axially outwardly from wall 151 and receiving the innermost portion 162 of end pin 112, said p-in being fixed within tubular portion 155 by conventional means such as welding. Extending radially outwardly from tubular portion 155 to shell 144 are brace members 156 which may be in the form of I-be-ams as shown in FIGURE 7.

Shell 144, at its outermost extremity, has an opening 154 through which air circulates for cooling the interior of connecting means 122.

Referring now to FIGURE 9, the embodiment of vessel 211 illustrated therein comprises a crucible portion shell 240 defined by a surface 247 symmetrical about a crucible axis 241 extending transversely to the axis 242 of pins 212. Surface 247 has a pair of cut-outs 270 each on an opposite side of crucible axis 241 and each located about or encircling pin axis 242.

Fixedly connecting pins 212 at respective opposite sides of crucible portion shell 240 are connecting means 222 each having a shell 244 defined by surface of revolution 248 having the axis 242 of the pins as a linear directrix and having a generatrix whose radial distance from pin axis 242 decreases in an outward direction relative to pin Crucible shell 240 terminates, in an outward direction along pin axis 242 and on each side of crucible axis 241, at a side peripheral edge 245 defined by cut-out 270. The shell 244 of each connecting means 222 terminates, in an inward direction along the pin axis 242 at an inner peripheral edge 246. The inner peripheral edge 246 of each connecting means shell 244 has the same dimensions as adjacent side peripheral edge 245 of crucible shell 240 around the entirety of each peripheral edge. The edges 245, 246 are in abutting relation, and, as a result, connecting means shell 244 constitutes a smooth, uninterruped continuation of crucible portion shell 240; and the shell of the entire vessel 211 has no projections or obstructions.

Crucible shell 240 is composed of vertically stacked horizontally disposed sections including, from bottom to top, a lowermost dished portion 280, a partially dished ring portion 281, a frusto-conical portion 282, a second ring portion 283, including cut-outs 270, a second frustoconcial portion 284 having an upper flange 285, and an uppermost frusto-conical portion 286 having a lower flange 287 abutting uppermost flange 285 of section 284. The sections 280284 and 286 would all have a curved outline if viewed in a horizontal sectional plane.

In constrast, the crucible portion 340 of the embodiment 311 illustrated in FIGURES and 11 is composed of vertically curved horizontally adjacent sections 382 all of which have a linear outline when projected on plane perpendicular to the crucible shell axis 341. Thus the crucible portion 340 has a polygonal outline when viewed from above (FIG. 11). Located below sections 382 are dished sections 380. Crucible portion shell 340 has a surface 347 symmetrical about the vertical axis 341 of the crucible and includes cut-outs 370 substantially identical to the cut-outs 270 in the embodiment 211 illustrated in FIGURE 9.

Aside from the fact that embodiment 311 has a poly onal outline when viewed in horizontal cross-section, where-as embodiment 211 of FIGURE 9 would have a circular or curved outline when viewed in horizontal crosssection, the embodiments 311 and 211 are otherwise substantially identical. In both embodiments 211 and 311, the shell of the vessel is directly connected to pins about which the vessel is rotated, and the vessel shell is selfsupporting. In the embodiments 311, the connecting means shell 344 constitutes a smooth, uninterrupted continuation of the crucible portion shell 340, just as in the case of the corresponding shells 244, 240 in the embodiment 311 of FIGURE 9. In either embodiment, 211 or 311, construction is facilitated because most of the crucible shell sections need be formed with a curvature in only a single direction; i.e., only a horizontal curvature for sections 282-284 and 286 of embodiment 211, and only a vertical curvature for section 382 of embodiment 311.

There have thus been described embodiments of molten metal refining apparatus including a metallurgical vessel having a self-supporting shell which is directly connected to the end pins about Whose axis the vessel is rotated.

-The above-described vessel and apparatus are relatively simple in construction, relatively easy to fabricate, and relatively economical in cost.

Contributing to the economy, in addition to the fact that the mounting arrangement is relatively simple and 6 inexpensive, is the fact that in certain embodiments, the volume defined by the shell of the entire vessel is substantially less than the volume defined by the entire first surface of revolution, a portion of which contributes to the shape of the crucible portion of the vessels shell. Accordingly, a substantially smaller amount of plate is required to construct the vessel shell than would be required if the vessel shell were defined entirely by the first surface of revolution.

For example, referring to FIG. 3, if the vessel shell were defined entirely by the first surface of revolution 47 the vessel would follow the profile indicated by dash-dot line 147 rather than follow the profile of the surface of revolution 48 defining connecting means shell 44.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary litmitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

What is claimed is:

1. Molten metal refining apparatus comprising:

a crucible portion having an outer shell;

a pair of substantially coaxially aligned end pins each located on an opposite side of said crucible portion; means mounting said pins for rotation about a common axis;

said crucible portion shell being defined by a first surface of revolution having a linear directrix extending transversely to the axis of said pins and by a pair of planes each extending transversely to the axis of the pins and each intersecting said surface of revolution on an opposite side of said directrix; a pair of means each fixedly connecting the axially inner portion of a respective pin to a respective opposite side of said crucible portion;

each of said connecting means including a shell defined by a sunface of revolution having the axis of a respective pin as a linear directrix and having a generatrix whose radial spacing from the pin axis decreases in an outward direction relative to said pin;

the shell of each of said connecting means being a smooth, uninterrupted continuation of the shell of said crucible portion;

said crucible portion shell terminating, in an outward direction along the axis of said pins, and on each side of said crucible directrix, at a side peripheral edge lying in a respective one of said planes intersecting said first surface of revolution;

the shell of each connecting means terminating, in an inward direction along the axis of the pins, at an inner peripheral edge lying in the same plane as that in which an adjacent side peripheral edge of said crucible shell lies;

the inner peripheral edge of each connecting means shell being in abutting relation with the adjacent side peripheral edge of said crucible shell around the entirety of each peripheral edge;

an oxygen lance;

an opening in said crucible portion for receiving said oxygen lance;

means mounting said oxygen lance for reciprocal move ment into and out of said opening in the crucible portion;

and a refractory lining located within said shells.

2. An apparatus as recited in claim 1 wherein:

the volume defined by the entire shell of said vessel being substantially less than the volume defined by said first surface of revolution.

3. An apparatus as recited in claim 1 wherein each of said connecting means comprises:

a cylindrical tubular portion, located radially inwardly of said connecting means shell, for receiving the axially innermost portion of an end pin;

brace means extending between said cylindrical tubular portion and said shell of the connecting means;

and a plate between the tubular portion and the shell,

located axially inwardly of said bracing means.

'4. An apparatus as recited in claim 3 wherein:

each of said connecting means comprises opening means between the shell and tubular portion for ventilating the interior of the connecting means.

'5. An apparatus as recited in claim 1 wherein:

said connecting means shell has the shape of the frustum of a cone.

6. A metallurgical vessel comprising:

a crucible portion having an outer shell;

a pair of substantially coaxially aligned end pins each located on an opposite side of said crucible portion;

said crucible portion shell being defined by a first surface of revolution having a linear directrix extending transversely to the axis of said pins and by a pair of planes each extending transversely to the axis of the pins and each intersecting said surface of revolution on an opposite side of said directrix;

a pair of means each fixedly connecting the axially inner portion of a respective pin to a respective oppos-ite side of said crucible portion;

each of said connecting means including a shell defined by a surface of revolution having the axis of a respective pin as a linear directrix and having a generatr-ix whose radial spacing from the pin axis decreases in an outward direction relative to said pin;

the shell of each of said connecting means being a smooth, uninterrupted continuation of the shell of said crucible portion;

said crucible portion shell terminating, in an outward direction along the axis of said pins, and on each side of said crucible directrix, at a side peripheral edge lying in a respective one of said planes intersecting said first surface of revolution;

- the shell of each connecting means terminating, in an in- Ward direction along the axis of the pins, at an inner peripheral edge lying in the same plane as that in which an adjacent side peripheral edge of said crucible shell lies;

the inner peripheral edge of each connecting means shell being in abutting relation with the adjacent side peripheral edge of said crucible shell around the entirety of each peripheral edge;

an opening in the shell of said crucible portion;

and a refractory lining located within said shells.

7. A metallurgical vessel as recited in claim 6 wherein:

the volume defined by the entire shell of said vessel being substantially less than the volume defined by said first surface of revolution.

8. A metallurgical vessel as recited in claim 6 wherein each of said connecting means comprises:

a cylindrical tubular portion, located radially inwardly of said connecting means shell, for receiving the axially innermost portion of an end pin;

brace means extending between said cylindrical tubular portion and said shell of the connecting means;

and a plate between the tubular portion and the shell,

located axially inwardly of said bracing means.

9. A metallurgical vessel as recited in claim 8 wherein:

each of said connecting means comprises opening means between the shell and tubular portion for ventilating the interior of the connecting means.

10. A metallurgical vessel as recited in claim 6 wherein:

said connecting means shell has the shape of the frustum of a cone.

11. Molten metal refining apparatus comprising:

a crucible portion having an outer shell;

a pair of substantially coaxially aligned end pins each located on an opposite side of said crucible portion;

means mounting said pins for rotation about a common axis;

said crucible portion shell being defined by a first surface of revolution having a linear directrix extending transversely to the axis of said pins and by a pair of planes each extending transversely to the axis of the pins and each intersecting said surface of revolution on an opposite side of said directrix;

a pair of means each fixedly connecting the axially inner portion of a respective pin to a respective opposite side of said crucible portion;

each of said connecting means including a shell defined by a surface of revolution and a pair of planes intersecting said surface of revolution, a first of said pair of planes coinciding with a respective one of said first recited pair of planes intersecting said first surface of revolution, and the second of said planes being located outwardly of said first plane along the axis of said' pins and extending transversely to the axis of said pins;

the shell of each of said connecting means being a smooth, uninterrupted continuation of the shell of said crucible portion;

said crucible portion shell terminating, in an outward direction along the axis of said pins, and on each side of said crucible directrix, at a side peripheral edge lying in a respective one of said first pair of planes intersecting said first surface of revolution;

the shell of each connecting means terminating, in an inward direction along the axis of the pins, at an inner peripheral edge lying in the same plane as that in which an adjacent side peripheral edge of said crucible shell lies;

the inner peripheral edge of each connecting means shell being in abutting relation with the adjacent side peripheral edge of said crucible shell along the entirety of each peripheral edge;

the volume defined by the entire shell of said vessel being substantially less than the volume defined by said first surface of revolution;

an oxygen lance;

an opening in said crucible portion for receiving said oxygen lance;

means mounting said oxygen lance for reciprocal movement into and out of said opening in the crucible portion;

and a refractory lining located Within said shells.

12. A metallurgical vessel comprising:

a crucible portion having an outer shell;

a pair of substantially coaxially aligned end pins each located on an opposite side of said crucible portion;

said crucible portion shell being defined by a first surface of revolution having a linear directrix extending transversely to the axis of said pins and by a pair of planes each extending transversely to the axis of the pins and each intersecting said surface of revolution on an opposite side of said directrix;

a pair of means each fixedly connecting the axially inner portion of a respective pin to a respective opposite side of said crucible portion;

each of said connecting means including a shell defined by a surface of revolution and a pair of planes intersecting said surface of revolution, a first of said pair of planes coinciding with a respective one of said first recited pair of planes intersecting said first surface of revolution, and the second of said planes being located outwardly of said first plane along the axis of said pins and extending transversely to the axis of said pins;

the shell of each of said connecting means being a smooth, uninterrupted continuation of the shell of said crucible portion;

said crucible portion shell terminating, in an outward direction along the axis of said pins, and on each side of said crucible directrix, at a side peripheral edge lying in a respective one of said first pair ofv planes intersecting said first surface of revolution; the shell of each connecting means terminating, in an inward direction along the axis of the pins, at an inner peripheral edge lying on the same plane as that 9 in which an adjacent side peripheral edge of said crucible shell lies; the inner peripheral edge of each connecting means shell being in abutting relation with the adjacent side peripheral edge of said crucible shell along the entirety of each peripheral edge;

the volume defined by the entire shell of said vessel being substantially less than the volume defined by said first surface of revolution;

an opening in the shell of said crucible portion;

and a refractory lining located within said shells.

13. A metallurgical vessel comprising:

a crucible having an outer shell;

a pair of substantially coaxially aligned end pins each located on an opposite side of said crucible;

said crucible shell being defined by a surface disposed around a crucible shell axis extending transversely to the axis of said pins;

said crucible shell surface having a pair of cut-outs each disposed on an opposite side of the crucible shell axis and each disposed around the axis of the pins;

a pair of means each fixedly connecting the axial inner portion of a respective pin to a respective opposite side of said crucible;

each of said connecting means including a shell defined by a surface disposed around the axis of a respective pin;

the shell of each of said connecting means being a smooth, uninterrupted continuation of the shell of said crucible;

said crucible shell terminating, in an outward direction along the axis of said pins, and on each side of said crucible shell axis, at a side peripheral edge defined It) by a respective cut-out and disposed about the axis of the pins; the shell of each connecting means terminating, in an inward direction, along the axis of the pins, at an inner peripheral edge having the same dimensions as the side peripheral edge defined by said cut-outs; the inner peripheral edge of each connecting means shell being in abutting relation with the adjacent side peripheral edge of said crucible shell around the entirety of each peripheral edge;

an opening in the shell of said crucible;

and a refractory lining located within said shells.

14. A vessel as recited in claim 13 wherein:

said crucible shell surface is symmetrical about said crucible axis;

and said connecting means shell is symmetrical about said pin axis.

15. A vessel as recited in claim 13 wherein:

said crucible portion shell has a polygonal cross-section in a plane perpendicularto the crucible sh'ell axis.

16. A vessel as recited in claim 13 wherein:

said crucible portion shell is composed substantially of sections which are curved in only a single direction.

17. In combination with the vessel recited in claim 13:

an oxygen lance;

an opening in said crucible portion for receiving said oxygen lance;

and means mounting said oxygen lance for reciprocal movement into and out of said opening in the'crucible portion.

No references cited.

JOHN F. CAMPBELL, Primary Examiner.

M. L. FAIGUS, Assistant Examiner. 

1. MOLTEN METAL REFINING APPARATUS COMPRISING: A CRUCIBLE PORTION HAVING AN OUTER SHELL; A PAIR OF SUBSTANTIALLY COAXIALLY ALIGNED END PINS EACH LOCATED ON AN OPPOSITE SIDE OF SAID CRUCIBLE PORTION; MEANS MOUNTING SAID PINS FOR ROTATION ABOUT A COMMON AXIS; SAID CRUCIBLE PORTION SHELL BEING DEFINED BY A FIRST SURFACE OF REVOLUTION HAVING A LINEAR DIRECTRIX EXTENDING TRANSVERSELY TO THE AXIS OF SAID PINS AND BY A PAIR OF PLANES EACH EXTENDING TRANSVERSELY TO THE AXIS OF THE PINS AND EACH INTERSECTING SAID SURFACE OF REVOLUTION ON AN OPPOSITE SIDE OF SAID DIRECTRIX; A PAIR OF MEANS EACH FIXEDLY CONNECTING THE AXIALLY INNER PORTION OF A RESPECTIVE PIN TO A RESPECTIVE OPPOSITE SIDE OF SAID CRUCIBLE PORTION; EACH OF SAID CONNECTING MEANS INCLUDING A SHELL DEFINED BY A SURFACE OF REVOLUTION HAVING THE AXIS OF A RESPECTIVE PIN AS A LINER DIRECTRIX AND HAVING A GENERATRIX WHOSE RADIAL SPACING FROM THE PIN AXIS DECREASES IN AN OUTWARD DIRECTION RELATIVE TO SAID PIN; THE SHELL OF EACH OF SAID CONNECTING MEANS BEING A SMOOTH, UNITERRUPTED CONTINUATION OF THE SHELL OF SAID CRUCIBLE PORTION; SAID CRUCIBLE PORTION SHELL TERMINATING, IN AN OUTWARD DIRECTION ALONG THE AXIS OF SAID PINS, AND ON EACH SIDE OF SAID CRUCIBLE DIRECTRIX, AT A SIDE PERIPHERAL EDGE LYING IN A RESPECTIVE ONE OF SAID PLANES INTERSECTING SAID FIRST SURFACE OF REVOLUTION; THE SHELL OF EACH CONNECTING MEANS TERMINATING, IN AN INWARD DIRECTION ALONG THE AXIS OF THE PINS, AT AN INNER PERIPHERAL EDGE LYING IN THE SAME PLANE AS THAT IN WHICH AN ADJACENT SIDE PERIPHERAL EDGE OF SAID CRUCIBLE SHELL LIES; THE INNER PERIPERAL EDGE OF EACH CONNECTING MEANS SHELL BEING IN ABUTTING RELATION WITH THE ADJACENT SIDE PERIPHERAL EDGE OF SAID CRUCIBLE SHELL AROUND THE ENTIRETY OF EACH PERIPHERAL EDGE; AN OXYGEN LANCE; AN OPENING IN SAID CRUCIBLE PORTION FOR RECEIVING SAID OXYGEN LANCE; MEANS MOUNTING SAID OXYGEN LANCE FOR RECIPROCAL MOVEMENT INTO AND OUT OF SAID OPENING IN THE CRUCIBLE PORTION; AND A REFRACTORY LINING LOCATED WITHIN SAID SHELLS. 